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Access to Vinyl Ethers and Ketones with Hypervalent Iodine Reagents as Oxy‐Allyl Cation Synthetic Equivalents
Author(s) -
Declas Nina,
Waser Jerome
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202006707
Subject(s) - hypervalent molecule , umpolung , chemistry , nucleophile , enol , reagent , aryl , reactivity (psychology) , silylation , organic chemistry , medicinal chemistry , nucleophilic addition , catalysis , alkyl , medicine , alternative medicine , pathology
We report an Umpolung strategy of enol ethers to generate oxy‐allyl cation equivalents based on the use of hypervalent iodine reagents. Under mild basic conditions, the addition of nucleophiles to aryloxy‐substituted vinylbenziodoxolone (VBX) reagents, easily available in two steps from silyl alkynes, resulted in the stereoselective formation of substituted aryl enol ethers. The reaction was most efficient with phenols as nucleophiles, but preliminary results were also achieved for C‐ and N‐ nucleophiles. In absence of external nucleophiles, the 2‐iodobenzoate group of the reagent was transferred. The obtained aryl enol ethers could then be transformed into α‐difunctionalized ketones by oxidation. The described “allyl cation”‐like reactivity contrast with the well‐established “vinyl‐cation” behavior of alkenyl iodonium salts.